1. Field of the Invention
The present invention relates to a plastic syringe which is provided at its rear end with a flange and which is pre-filled with a liquid medicament, and an adaptor system composed of such a medicament-prefilled syringe and a plastic flange adaptor which is attached to the flange of the plastic syringe.
2. Description of the Related Art
In a known medicament-prefilled syringe system, a syringe which has been filled with a liquid medicament is prepared and is adapted, upon dosage, to inject the liquid medicament contained in the syringe into a patient's body by moving the plunger of the syringe. In this medicament-prefilled syringe system, the syringe is provided, on the outer peripheral surface thereof, with a label which bears information including the name and/or ingredients of the liquid medicament contained in the syringe.
Upon injection of the liquid medicament from the syringe, in general, an operator moves the plunger using his or her thumb while holding the flange provided at the rear end of a cylinder of the syringe with the operator's index finger and middle finger. However, the flange at the rear end of the syringe is so small that it is difficult for the operator to carry out a smooth injection depending on the viscosity of the liquid medicament or the external force exerted on the plunger by the operator. To solve this problem, an additional flange adaptor whose diameter is larger than that of the rear flange of the syringe is attached to the flange at the rear end of the cylinder of the syringe according to need. To attach the flange adaptor, the syringe is inserted in the flange adaptor, with the end of the syringe that is located away from the flange being the leading end. When the larger flange adaptor is attached to the syringe, the flange adaptor abuts against the flange of the syringe, so that the diameter of the flange is substantially increased.
In order to give a secure feeling of the adapter being in place and a secure feeling thereof when in use, it is preferable that the flange adaptor be firmly fitted onto the outer peripheral surface of the cylinder of the syringe or be in close contact with the rear flange of the syringe. However, if the flange adaptor is firmly fitted onto the outer peripheral surface of the syringe body, the label provided on the outer peripheral surface of the syringe body can easily be rubbed by the flange adaptor upon attachment thereof, so that the label may possibly get separated or damaged. If separation or damage of the label occurs, there is a danger of the operator not being able to identify the liquid medicament contained in the syringe.